Qualification > Sciences
Biolgy paper 1 help!
nid404:
it was D dude.
cause when sewage is added bacteria feed on the organic matter,using a lot of dissolved oxygen. When this happens fishes have less oxygen to thrive on(they die). When they die it depletes oxygen levels more....so bacteria which do not require oxygen(anaerobically respiring bacteria)will increase cuz they can survive without oxygen
john12345:
Heyy
nd what was the answer for which of dese carry glucose
was it arteries only
or arteries and veins
was dat a difficult question or am i just too stupid to have got the wrong answer for that
Friends:
--- Quote from: nid404 on June 06, 2009, 05:14:27 am ---it was D dude.
cause when sewage is added bacteria feed on the organic matter,using a lot of dissolved oxygen. When this happens fishes have less oxygen to thrive on(they die). When they die it depletes oxygen levels more....so bacteria which do not require oxygen(anaerobically respiring bacteria)will increase cuz they can survive without oxygen
--- End quote ---
Sorry man I dont agree with U.
See when oxygen level decreases,the fishes starts to die.
so the number of bacteria increase as they feed on dead fishes.
as from first the oxygen is less they respire anaerobically.
And how can dying of fish decrease oxygen level...???
Friends:
Ok i got the Answer.
If anyone uses Study guide of IGCSE for biology by Dave Haywaed
Plz see page no 128.
Highest is oxygen
then Algea
then nitrates
then suspended solids
then sewage fungus
IG_ICE09:
the sewage one HAS TO be "number of bacteria increase" as the first stage, so i think it started with 4-x-x-x as the order of events...i4got if it was C or D but when sewage is let in2 a river first the no of bacteria increase thats obvious, THEN they start depleting oxygen levels, fish die, and as a result, more anaerobic organisms (hu can survive without O2) are remaining.
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